Bleaching compositions comprising hydrogen peroxide and bleach activators have been described in the art. The bleach activator reacts with the hydrogen peroxide to yield a peracid which is the bleaching species.
Activated bleaching compositions however have the drawback that the activator and the hydrogen peroxide tend to react in the composition. Such activated bleaching compositions may be chemically unstable upon storage.
Another problem is that bleach activators which are hydrophobic, such as acylated citrate esters, are problematic to use in aqueous compositions because product may separate into two different layer phases which can be seen by the consumer. Therefore, physical stability upon storage is a further issue.
The present invention includes an aqueous cleaning and bleaching composition with a pH of from about 0.5 to about 6.0, comprising amidoperoxyacid, hydrogen peroxide, and acylated citrate ester which has been emulsified in ethoxylated alcohols with a weighted average Hydrophilic-Lipophilic Balance equal to that of the acylated citrate ester. The compositions allow for good flexibility in formulating and are chemically and physically stable on storage. As an additional benefit, the ethoxylated alcohol mixture used to emulsify the activator provides efficient cleaning.
Before making up the formulations of the present invention, it was expected that the amidoperoxyacid would react with the other active ingredients in the composition, particularly the hydrogen peroxide and the activator, adversely affecting the chemical and physical stability of the product and impairing bleaching performance of the amidoperoxyacid. It was also expected that the amidoperoxyacid would dissolve in the composition and recrystallize, causing the product to gel. Surprisingly, the present compositions containing amidoperoxyacid are physically and chemically stable and clean and bleach well.
U.S. Pat. No. 5,118,436, Aoyagi et al, issued Jun. 2, 1992 discloses an acidic liquid bleaching composition comprising hydrogen peroxide, anionic and nonionic surfactants, polyacrylic acid and/or maleic polymer, and polyphosphoric, amino phosphonic, or diphosphonic acids, or salts thereof.
U.S. Pat. No. 4,828,747, Rerek et al., issued May 9, 1989 discloses an aqueous liquid bleaching composition of pH 1-6.5 comprising a solid, particulate, substantially water insoluble organic peroxyacid which is said to be stably suspended by a structuring combination of anionic surfactant, ethoxylated nonionic surfactant and fatty acid.